Personal computers and other similar devices have a multitude of possibilities for providing user input. For instance, most computers today are used in conjunction with a mouse or similar pointing device for controlling the position of a cursor on a display. The mouse is also often used for scrolling in, e.g., word processing applications or other similar applications.
However, the mouse is not always an optimal device for controlling scrolling. Although some mice have scroll wheels, these wheels are also not ideal for some users, as they require substantial manual dexterity to be able to control the mouse, mouse wheel, and mouse buttons simultaneously. Another reason a mouse is not necessarily optimal for scrolling is that it requires a user who is typing on a keyboard to remove one of his or her hands from the keyboard to the mouse, and then back to the keyboard to continue typing.
There is therefore a need for an alternative device for controlling scrolling. To address the above problems, others have attempted to provide scrolling via the use of a two-dimensional touch pad such as that found on a typical laptop computer. For instance, the user can scroll by dragging a finger along an edge of the touch pad. However, the two-dimensional touch pad is not always convenient because of the tendency to not be able to place the finger accurately on the edge of the touch pad. Further, inaccurate touching of the touch pad will move the cursor instead of scrolling, causing frustration to the user.
There is also a need for a better way to sense the position of a finger on a touch sensitive position sensor that corrects for common-mode errors such as variations in finger pressure, fingertip size, moistness of the finger caused by hand lotion, and other factors.